Drain seal for metal receptacles



United States Patent [72] Inventors William V. Armstead [56] References Cited 102.12 w Will-imam; UNITED STATES PATENTS ga gs 500,386 6/1893 Hartman 266/42 P 2,005,311 6/1935 Belding 222/559 [221 1968 a 124 854 3/1964 Dore 222/ss9x d Nov 17 1970 T451 meme 1 3,398,945 8/1968 wa1 61e 266/42 Primary Examiner-Robert B. Reeves Assistant Examiner-Frederick R. l-landren Attorney- Wells & St. John 1 DRAIN SEAL Q METAL RECEPTACLES ABSTRACT: An apparatus for sealing the flow of metal from 3 ohms 3 Dram" a molten metal receptacle using a conical plug fitted within a [52] US. (I 222/ 146, complementary orifice of a tapping block. A resilient refracto- 222/542, 222/563, 266/42 ry fiberpad covers the plug and a mat of grass fiber is inter- [51] lnt.Cl .L 867d 3/00, posed between the plug and the pad to provide economical C2lb 7/12 backing for the relatively expensive pad. In one embodiment, [50] Field of Search 222/559, the plug. is hollow and cooling air is provided about the line of 563, I46, 542; 266/42 contact between the plug and orifice.

.r A l5 z N J --n l 9 w Patented Nov. 17, 1970 3,540,627

W/LL/AM v. ARMSTEAD WILL/AM M. PEAK DRAIN SEAL FOR METAL RECEPTACLES BACKGROUND OF THE INVENTION In the handling of molten metal, such as aluminum, it is a common practice to utilize molten metal receptacles such as open hearths or various types of furnaces provided with replaceable tapping blocks having a cylindrical orifice. During transfer of molten metal from the receptacle, the metal passes through this orifice, and during heating operations, the orifice is maintained in a closed condition by means of a conical plug. For many years, such conical'plugswere coated with material such as a mixture of flour and water. known as dough" and the sealing of the orifice by this means was generally referred to as doughballing.

Recent developments have led to substantial use of replaceable conical pads of resilient refractory metal to coat the conical surfaces of the plug. An example of such usage is described and illustrated in U.S. Pat. No. 3,124,854, titled Refractory Stopper for Aluminum Casting Apparatus and Method of Casting". According to that patent, a resilient refractory material is used to cover the plug in the area of contact between the plug and the orifice. The type of refractory material disclosed is stated to be of primary importance, and

the best suited material is stated to be aluminum silicate fiber materials-such as'the material sold under the tradename of Fiberfrax.

One difficulty with the use ofigsuch. refractory materials as covers for the plug is the expense of using these specialized materials as expendable covers which can onlybe used in contact withthe very hot molten metal while they remain physically intact. In some situations, it has become common to use many layers of the conical covers to provide adequate resiliency so that the plug can effectively seal about the periphery of the orifice and accommodate variations in the orifice configuration.'The use of the refractory material is expensiveand the cost of multiple layers eventually becomes prohibitive. Accordingly, the basic concepts'disc losed herein are designed to minimize the expense of using such refractory pads and to minimize overheating and deterioration of the pads.

SUMMARY OF THE INVENTION According to this disclosure, an intermediate glass fiber mat is interposed between the pad of resilient 'refractory'material and the 'conicalplug in the area of contact between the plug and orifice. The relative inexpensive glass fiber mat provides the added resiliency in the covering assembly and minimizes the expense of the total assembly. It also provides improved insulation to the pad surfaces so that'the metal at the orifice does not tend to cool and seal the orifice. Under current practice the metal after freezing at the tapping block, cannot be removed without burning through the orifice opening. This frequently leads to damage of the block.

Besides the use of the glass-fiber mat, there is an additional alternative claimed herein, which involves the provision of cooling air provided in the plugthrough the mat surfaces at the contact area about the orifice. This protects the mat and outer pad from overheating, while maintaining the major portion of the orifice inthe desired insulated condition. Slight cooling orfreezing of the metal about the edges-of the orifice do-not detract from: the ability of the orifice to provide the I required flow of metalwhen the plug has been removed.

' glass fiber,'preferably about one-half inch in thickness. The

These and further objects will become more evident in connection with the following disclosure and the accompanying drawings. It is to be understood that the structure shown in the drawings is presented only by way of illustration and that the present disclosure is not to be limited specifically to the precise features shown.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view taken through a tapping block of a molten metal receptacle, showing the present apparatus in actual use;

FIG. 2 is an enlarged sectional view through the center of a typical plug, showing the covering apparatus in detail; and

FIG. 3 is another sectional view through a modified plug and covering apparatus, with .the outline of the orifice periphery at the top and bottom of the view being illustrated in dashed lines.

PREFERRED EMBODIMENT OF THE INVENTION The structure to which the disclosure relates is well shown in the prior art, particularly in [1.8. Pat. No. 3,124,854. Therefore, the present disclosure will not go into detail with respect tothe apparatus for holding the plug. in place nor the apparatus by which the tapping block is held in the receptacle. The present disclosure is readily applicableto any conventional structure used for these basic purposes.

As shown, there is illustrated a portion of a molten metal receptacle l0having an inserted tapping block 11 including a cylindrical orifice at 12. The molten metal within receptacle 10 is shown generally at 13 and the orifice l2 is used to permit the flow of metal from the interior of the receptacle 10 when required. A conical plug is selectively held within orifice 12 by a supporting rod-J5 and associated mechanisms forholding it inplace or permitting its removal when required. The plug 1 14 is substantially conical, meaning that it has the shape of a dome, a frustrum of a cone or a cone with a rounded apex.

The plug .obviously can ,be of a shape other than conicaLso long as the configuration ot thecontacting portions of the plug 010 asbestos sheeting, having a thickness of approximately.

. one-thirty second of an inch.

To provide resiliency and insulating properties to the plug assembly, we utilize an intermediate layer 17 of insulating layer 17 is a relatively high density mat of glass fibers or glass wool. Asuitable product is sold under the trade name Air- .core in one-half inch thick sheets by Owens-Corning. As

. eliminated if desired. The layers 16 and 18 are preferably of refractorymaterial alone. when using multiple cones of the refractory material, the metal sometimes freezes atorifice 12 due to the conduction of heat through the conical plugl4. This generally requires the metal to be burned atthe orifice .and ruins the orifice, which is relatively expensive to replace.

By use of the insulating layers l7, the metal at the orifice remains heated and does not freeze. Furthermore, the 1-inch mat provides additional resiliency to the assembly to accommodate variations in the orifice configuration and to securely seal orifice l2 abuts its entire periphery. 7

FIG. 3 illustrates a modification of the structure. In this modification, the plug 20 has the general exterior configuration shown in FIGS. 1 and 2, but is formed with an interior hollow cavity at 21. The cavity 21 is in open communication with a hollow mounting rod 22 through which compressed air can be supplied to cavity 21. A series of radial openings 23 are provided through the conical shell of the plug 20, being directed generally to the area of the plug exterior adjacent to the contacting line of orifice 12. The outer portion of orifice 12 is shown in dashed line for reference purposes.

The object of providing a hollow plug 20 is to permit the passage of compressed airthrough plug 20 and openings 23 to the area of contact between the covering materials and the orifice 12. As shown, the plug 20 is covered by a conical pad of refractory material 16 and a layer of insulating glass material 17. The layer 16 might be asbestos and the layer 17 a suitable dense insulating glass fiber mat or a mat of glass wool. The cooling air directed through the openings 23 prevents the glass at the line of contact from deteriorating under the heat to which it is subjected and the pressure exerted through the pad 16. This greatly extends the life of the insulating mat. Although some metal might freeze about the periphery of the orifice 12, the remaining portions of the conical pad 16 are still fully insulated as before, and the metal will not freeze across the entire orifice 12. The use of cooling air extends the life of the glass material and prevents its deterioration. It greatly extends the usefulness of an assembly of covering materials and permits it to be reused many more times than is possible when air is not utilized. A conventional air compressor (not shown) can be used to supply air through the rod 22 for cooling purposes.

Other modifications may be made in this assembly without deviating from the basic concept of providing effective resilient insulation behind the refractory pad. Therefore, the extend of this disclosure and the invention set out herein is not to be limited except as set out in the following claims.

We claim:

1. In an apparatus for sealing the flow of molten metal from a receptacle comprising:

a tapping block having a cylindrical orifice formed therethrough;

a conical plug having a maximum diameter greater than the diameter of the block orifice;

mounting means releasably connected between said receptacle and plug to hold the plug partially within the block orifice wherein a line of contact may be made between the outer peripheral surface of the plug and the inner peripheryv of the orifice; and

a resilient refractory fiber pad covering said plug about the conical surface thereof;

the improvement comprising:

a glass fiber mat outward of the conical plug and interposed between the pad and plug, the thickness of the mat being substantially in excess of the thickness of the pad, the mat completely overlying and covering the conical surface of the plug, including the area of contact between said plug and the orifice; and I said mat being secured to the pad as a unitary structure, the

pad and mat each being formed as coaxial conical members in surface to surface contact with one another.

2. The apparatus as set out in claim 1 further comprising a second resilient refractory fiber pad interposed between the plug and said mat.

3. In an apparatus for sealing the flow of molten metal from a receptacle comprising:

a tapping block having a cylindrical orifice formed therethrough;

a conical plug having a maximum diameter greater than the diameter of the block orifice; mounting means releasably connected between sad receptacle and plug to hold the plug partially within the block orifice wherein a line of contact may be made between the outer peripheral surface of the plug and the inner periphery of the orifice; and

a resilient refractory fiber pad covering said plug about the conical surface thereof;

the improvement comprising: i

a glass fiber mat interposed between said pad and said plug in the area of contact between said plug and the orifice;

a source of compressed air; and

means within said plug operatively connected to said source of compressed air for directing the air to said mat about the area of contact between the plug and the orifice. 

